The Federal Government is responsible for immigration. It's their job to set policies and adjudicate immigration issues.

Local and State Law Enforcement are not responsible for -- and indeed it is outside of their powers to enforce immigration laws.

Supreme Court precedent is that states cannot be compelled by Congress to enforce Immigration law (see: Printz v. United States).

So, what you have in this situation are the fact that States and the Federal Government have opposing interests: The States need to be able to enforce their laws without their people feeling like they can't tell the police when there's a crime, and the current federal policy is to deport all undocumented immigrants, no matter why they're here or whether they are allowed to be here while their status is adjudicated.